ACTIVATION OF THE EGG BY BASES 



153 



time of exposure was one hour and twenty-five minutes; the 

 temperature 18 C. The concentration of the bases chosen 

 was that found most effective in the writer's previous experi- 

 ments on artificial parthenogenesis. The oxygen consumption 

 was first measured in a neutral solution and then for the same 

 eggs in the alkaline solution in which . 3 c.c. N/10 of the various 

 bases was added to 50 c.c. of the solution. 



This influence of the various bases upon the rate of oxida- 

 tion in the eggs of purpuratus runs parallel to their relative 

 efficiency in causing development in Polynoe. To induce 

 artificial parthenogenesis in the eggs of Polynoe the simple 

 amines were found to be most efficient, next came NH 4 OH and 

 trimethylamine, and finally the strong bases NaOH and tetra- 

 ethylammoniumhydroxide. The amines seem to hurt the eggs 

 of purpuratus more than those of Polynoe. 



Incidentally it may be stated that NaHCO 3 does not 

 accelerate the rate of oxidations in the unfertilized egg, nor 

 does it cause artificial parthenogenesis. 



7. We compared next the relative effect of various concen- 

 trations of NaOH and NH 4 OH upon the rate of oxidations in 

 the unfertilized sea-urchin egg, during one hour. We will 

 state only the coefficient of the rate of oxidation in the various 

 solutions calling the rate in the neutral solution 1.00. 



TABLE XXVII 



AMOUNT OF BASE ADDED TO 

 50 c.c. m/2 (NaCl+KCl+ 



COEFFICIENT OF ACCEL- 

 ERATION OF OXIDA- 

 TIONS IN 



